The Impact Of Donor Type And ABO Incompatibility On Transfusion Requirements After Nonmyeloablative Hematopoietic Cell Transplantation (HCT)

Abstract

We retrospectively analyzed transfusion requirements within the first 100 days among 503 allogeneic HCT recipients with hematological malignancies given nonmyeloablative conditioning. We compared transfusion needs among recipients given grafts 1) from related (n=265) vs. unrelated donors (n=238), and 2) from ABO matched (n=292) vs. ABO mismatched donors (n=211); and 3) analyzed the impact of ABO incompatibility on nonmyeloablative HCT outcomes. Related recipients required less platelet and red blood cell (RBC) transfusions compared to unrelated recipients (P<0.0001 for both), with comparable median numbers of transfused units. Major/bidirectionally ABO-mismatched recipients required more RBC transfusions than ABO-matched recipients (P=0.006). Rates of graft rejection/failure, grades II-IV acute and chronic GVHD, 2-year relapse and 3-year survivals were comparable among ABO-matched, minor-mismatched, and major/bidirectionally mismatched recipients (P=0.93, 0.72, 0.57, 0.36 and 0.17, respectively). Times to disappearance of anti-donor IgG and IgM isohemagglutinins among major/bidirectionally ABO-mismatched recipients were affected by magnitude of pre-HCT titers (P<0.001 for both) but not by GVHD (P=0.71 and 0.78, respectively) and donor type (P=0.40 and 0.35, respectively). In addition, we compared overall transfusion needs among patients received myeloablative (n=1353) vs. nonmyeloablative HCT. We confirmed that myeloablative recipients required more platelet and RBC transfusions than nonmyeloablative recipients (both P<0.0001). Myeloablative patients given PBSC required less platelet transfusions (P<0.0001) than those given marrow while RBC transfusions did not differ significantly. Limiting the comparison to PBSC recipients given the two different conditionings did not change our findings. In conclusion, nonmyeloablative recipients required fewer platelet and RBC transfusions. Among them, both unrelated and major/bidirectionally ABO-mismatched recipients required more RBC transfusions. However, ABO incompatibility did not affect any of the nonmyeloablative HCT outcomes. Furthermore, anti-donor isohemagglutinin titers at the time of transplantation predicted the tempo of titer disappearance after transplantation.